SpringMVC 配置 & 初识 & 注解 &重定向与转发

初识

在web.xml 中注册DispatcherServlet

    <servlet>
        <servlet-name>springmvcservlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>

        <init-param>
            <param-name>contextConfigLocationparam-name>
            <param-value>classpath:springmvc-servlet.xmlparam-value>
        init-param>
        <load-on-startup>1load-on-startup>
    servlet>



    <servlet-mapping>
        <servlet-name>springmvcservlet-name>
        <url-pattern>/url-pattern>
    servlet-mapping>

在资源包中添加springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceView">

        <property name="prefix" value="/WEB-INF/jsp/"/>

        <property name="suffix" value=".jsp"/>

    bean>

    <bean id="/hello" class="com.ljm.controller.HelloController"/>

beans>

HelloController类

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","HelloSpringMVC");
        mv.setViewName("hello");  //WEB-INF/jsp/hello.jsp
        return mv;
    }
}

启动失败的话,若是代码无问题 显示404什么的可以看下IDEA的项目发布中,有没有添加lib有关依赖

添加后,在maven里面clean下生命周期 , 重启tomcat 就行

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使用注解开发

 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvcservlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
        
        <init-param>
            <param-name>contextConfigLocationparam-name>
            <param-value>classpath:springmvc-servlet.xmlparam-value>
        init-param>
        <load-on-startup>1load-on-startup>
    servlet>

    
    
    <servlet-mapping>
        <servlet-name>springmvcservlet-name>
        <url-pattern>/url-pattern>
    servlet-mapping>
web-app>

springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd
">



    <context:component-scan base-package="com.ljm.controller"/>

    <mvc:default-servlet-handler/>

    <mvc:annotation-driven/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceView">

        <property name="prefix" value="/WEB-INF/jsp/"/>

        <property name="suffix" value=".jsp"/>

    bean>



beans>

controller

@Controller   //完成之前bean的注册作用
//@RequestMapping("/hello")
//@RequestMapping可以作用于类 也可以作用于方法  一般选后者  两者都有的话url地址要叠加
public class HelloController  {

    @RequestMapping("/hello")  //真实访问地址   项目名/*/hello
    public String hello666(Model model){
        //封装数据
        model.addAttribute("msg","hello anno");
        return "jojohello";  //会被视图解析器处理  jsp目录下的jsp文件
    }

}

JSON格式返回的话用注解可以在类的上面标注@RestController   

@ResponseBody    //在方法的上面@

两者都不会走视图解析器,而是会直接返回一个字符串

视图(.jsp)可以被复用

重定向与转发